Carnosine, a compound with plethora of benefits, was originally discovered in 1900 and is formed by the amide linkage of β-alanine and L-histidine. Carnosine production is limited by β-alanine whereas the imidazole ring of histidine moiety makes it a suitable buffer in physiological pH range. It is reported to be found in the skeletal muscle, brain, heart, and gastrointestinal tissues of humans. This review focuses on the biological properties of carnosine including pH buffering ability, antioxidant activity, anti-inflammatory activity, anti-aging effect, enhancement of cognitive function, and immunomodulation. The relevance of carnosine in muscle function attributing to enhancement of physical performance has also been highlighted. Studies spanning several years have proved the preclinical effectiveness of carnosine in treating diverse pathological diseases. A complete summary of all key activities of carnosine from in vivo investigations and clinical trials has been compiled. Considering its numerous advantages, carnosine may be a promising option for the development of a nutraceutical.

Zinc L-carnosine is a pharmaceutical compound with direct mucosal cytoprotective and anti-inflammatory action through its antioxidative effects, cytokine modulation and membrane-stabilizing properties. Chemically, it is not an anti-secretory, antacid or raft-forming agent; its properties are mainly mediated by its higher affinity for damaged mucosa that permits the release of zinc locally by ligand exchange. Beneficial effects on various types of mucosal damage have been described in vitro and in vivo, in both animals and humans. It has been shown to promote repair of mucosal injury in human studies and has been widely used for the treatment of peptic ulcers, chemoradiotherapy-induced oral mucositis and esophagitis. More recently, the therapeutic applications of Zinc L-carnosine have been extended to the prevention and cure of various types of intestinal damage, including ulcerative colitis, iatrogenic ulcers after operative endoscopy, hemorrhoidal disease and impaired intestinal permeability. This review concentrates mainly on the current and future applications of zinc L-carnosine in gastrointestinal disease, and may be of use to gastroenterologists and endoscopists. It describes the therapeutic principles and benefits of this interesting molecule and discusses the potential future fields of interest for clinical use in humans.

Zinc (Zn) has an existence within large quantities in the human brain, while accumulating within synaptic vesicle. There is growing evidence that Zn metabolic equilibrium breaking participates into different diseases (e.g., vascular dementia, carcinoma, Alzheimer's disease). Carnosine refers to an endogenic dipeptide abundant in skeletal muscle and brains and exerts a variety of positive influences (e.g., carcinoma resistance, crosslinking resistance, metal chelation and oxidation limitation). A complex of Zn and carnosine, called Zinc-L-carnosine (ZnC), has been extensively employed within Zn supplement therapeutic method and the treating approach for ulcers. ZnC has been shown to play a variety of roles in the body, including inhibiting intracellular reactive oxygen species(ROS) and free radical levels, inhibiting inflammation, supplementing zinc enzymes and promoting wound healing and mucosal cell repair. The present study conducting a reviewing process for the advances of ZnC in tumor adjuvant therapy.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease associated with intestinal epithelial barrier impairment. Polydatin (PD), a natural product isolated from Polygonum cuspidatum, is known to have an anti-inflammatory, antioxidant, and antiapoptotic effect. We attempted to compare the protective impact of PD pretreatment on alterations to the intestinal epithelial barrier and the colonic wall's ultrastructure accompanying ulcerative colitis to other conventional drugs in practice, primarily L-carnosine, which has not been addressed before. The rats were divided into 5 groups; 3 of them were treated with sulphasalazine (500 mg/kg), L-carnosine (30 mg/kg), and PD (45 mg/kg). All groups were administered their respective drugs 3 days before the UC was induced by acetic acid intra-rectally, and the treatment was continued until the 11th day. The disease activity index (DAI) was estimated, and a macroscopic scoring was established for the harvested colonic tissue. The tissues were extracted and processed for hematoxylin and eosin staining, caspase-3 immunohistochemical staining, electron microscopy, and biochemical analysis evaluating proinflammatory markers (IL-1β, TNF-α, and IL-6), myeloperoxidase (MPO), oxidative stress, and lipid peroxidation. Histopathological examination of colonic tissue showed that PD pretreatment effectively restored mucosal epithelial cells, intercellular tight junctions, goblet cells, and maintained the intestinal epithelial and endothelial barriers. PD suppressed MPO, proinflammatory markers, and malondialdehyde but enhanced superoxide dismutase and glutathione levels. It also hampered apoptosis, as evidenced by a reduction in caspase-3 expression. PD showed a significantly better response in preserving the intestinal epithelial barrier against acetic acid-induced colitis as compared to sulphasalazine and L-carnosine. These findings demonstrate the therapeutic role of PD for patients with UC.

Nutritional deficiencies and malnutrition are considered to be related to ulcerative colitis (UC); however, the association between serum levels of micronutrients and UC is not well known. This study aimed to evaluate the serum levels of micronutrients in UC patients and investigate their association with disease activity.This cross-sectional study was conducted on UC patients visiting the Department of Gastroenterology at 3 different teaching hospitals between January 2016 and January 2017. UC activity was measured based on Truelove and Witts' severity index and guidelines for colonoscopy. A healthy gender- and age-matched group was also selected. Serum levels of zinc, copper, selenium, ceruloplasmin, albumin, and total protein were compared between the 2 groups of UC patients and healthy subjects using independent-samples t test. Also, the association between serum levels of micronutrients and UC activity was assessed by using Pearson and Spearman correlation coefficient tests. The data were analyzed by SPSS version 21, considering P ≤.05 as the statistical significance level.Overall, 112 (54 male and 58 female) individuals with the mean age of 34.6 years were studied in the 2 groups of UC patients (n = 56) and healthy subjects (n = 56). The 2 groups were homogeneous in terms of age, gender, marital status, place of residence, and educational level (P >.05). The serum levels of total protein (6.41 ± 1.1 vs 7.41 ± 0.4 g/dL; P = .0001), albumin (4.72 ± 1.1 vs 5.19 ± 0.28 g/dL; P = .0001), zinc (679 ± 62 vs 1055 ± 156 μg/L; P = .0001), and selenium (81.85 ± 6.4 vs 108.4 ± 12.98 micg/L; P = .0001) were significantly lower in the UC patients. The serum level of copper did not differ significantly between the 2 groups (P = .1).Considering the simultaneous reduction in nutritional criteria in the UC patient group, malnutrition appears to be a factor affecting micronutrient deficiency in patients with UC.

Cancer is one of the major causes of death worldwide, and the incidence and mortality rates of cancer are expected to rise tremendously in the near future. Despite a better understanding of cancer biology and advancement in cancer management, current strategies in cancer treatment remain costly and ineffective. Hence, instead of putting more efforts to search for new cancer cures, attention has now been shifted to the development of cancer chemopreventive agents as a preventive measure for cancer formation. It is well known that neoplastic transformation of cells is multifactorial, and the occurrence of oxidative stress, chronic inflammation, and genomic instability events has been implicated in the carcinogenesis of cells. Zinc l-carnosine (ZnC), which is clinically used as gastric ulcer treatment in Japan, has been suggested to have the potential in preventing cancer development. Multiple studies have revealed that ZnC possesses potent antioxidant, anti-inflammatory, and genomic stability enhancement effects. Thus, this review provides some mechanistic insight into the antioxidant, anti-inflammatory, and genomic stability enhancement effects of ZnC in relevance to its chemopreventive potential.

Polaprezinc (PZ), an antiulcer drug, has been reported to have antioxidant effects. The purpose of the present study was to assess the radioprotective effects of PZ in the normal intestine of C57BL/6J mice. PZ was orally administered at 100 mg/kg body weight in the drinking water. Firstly, the present study compared the survival of normal intestinal crypt epithelial cells with mice that received PZ prior to or following irradiation. Next, the present study examined the sequential changes of the incidence of apoptosis in the normal intestine of mice that received irradiation. The mice that received PZ prior to irradiation demonstrated a stronger protective effect on the normal intestine compared with those that received PZ after irradiation. The present study therefore administrated PZ 2 h before irradiation in the subsequent experiments. The mice receiving PZ developed fewer apoptotic cells in the duodenum, jejunum and ileum. Radiation-induced cell death occurred with a peak at position 10 or lower from the base of the crypt axis, and was subsequently reduced by PZ treatment. Pretreatment with PZ protected the normal intestinal tissues from radiation-induced apoptosis.

Iron has been suggested to affect the clinical course of type 2 diabetes (T2DM) as accompanying increased intracellular iron accumulation may provide an alternative source for reactive oxygen species (ROS). Although carnosine has proven its therapeutic efficacy in rodent models of T2DM, little is known about its efficacy to protect cells from iron toxicity. We sought to assess if high glucose (HG) exposure makes cultured human umbilical vein endothelial cells (HUVECs) and renal proximal tubular epithelial cells (PTECs) more susceptible to metal induced toxicity and if this is ameliorated by L-carnosine. HUVECs and PTECs, cultured under normal glucose (5 mM, NG) or HG (30 mM), were challenged for 24 h with FeCl3. Cell viability was not impaired under HG conditions nor did HG increase susceptibility to FeCl3. HG did not change the expression of divalent metal transporter 1 (DMT1), ferroportin (IREG), and transferrin receptor protein 1 (TFRC). Irrespective of glucose concentrations L-carnosine prevented toxicity in a dose-dependent manner, only if it was present during the FeCl3 challenge. Hence our study indicates that iron induced cytotoxicity is not enhanced under HG conditions. L-Carnosine displayed a strong protective effect, most likely by chelation of iron mediated toxicity.

Polaprezinc (PZ), an antiulcer drug, has been reported to have antioxidant properties. The aim of the present study was to assess the feasibility and efficacy of administering PZ for radiation-induced mucositis in head and neck cancer patients. Patients with newly diagnosed head and neck cancer were enrolled in this prospective study. PZ was prepared as an oral rinse. The PZ oral rinse was used four times per day during the course of radiotherapy. Sequential changes in radiation mucositis were assessed during and after radiotherapy according to the Common Terminology Criteria for Adverse Events, version 3.0. Furthermore, a retrospective comparison analysis was performed to assess the efficacy of PZ for radiation-induced mucositis. A total of 32 patients were enrolled in the prospective study of the PZ oral rinse. Radiotherapy was performed up to a total dose of 60-66 Gy using a conventional schedule combined with chemotherapy. Of the 32 patients, 30 (93.8%) reported no complaints due to the PZ oral rinse. In addition, PZ was not associated with severe adverse effects. Among the patients who received PZ, grade 3 mucositis was observed in 29.0% based on the mucosal findings and in 39.3% based on the symptoms. In the patients who did not receive PZ, the incidence of grade 3 mucositis was 40.0% based on the mucosal findings and 60.7% based on the symptoms. Moreover, PZ promoted the recovery from mucositis caused by chemoradiotherapy and was not associated with reduced tumor response to radiotherapy. Therefore, the PZ oral rinse was well tolerated and proved to be efficient for the treatment of radiotherapy-induced oral mucositis.

This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases.

Ulcerative colitis (UC) is a chronic, relapsing and remitting intestinal inflammatory disorder. Zinc is known to be efficacious for the repair of damaged tissue and has been shown to protect against gastric ulceration. This study focused on Polaprezinc (PZ), N-(3-aminopropionyl)-L-histidinato zinc, which accelerates ulcer healing through actions such as prostaglandin-independent cytoprotection and antioxidative activity.

In this randomized, placebo-controlled, investigator-blinded trial, 28 patients with active UC at The Jikei University Hospital were randomly divided into two groups: one treated with a 150 mg PZ enema (n = 18) and the other not treated with a PZ enema (n = 10). All patients received usual induction therapy. Clinical symptoms, endoscopic findings and histological findings were evaluated at entry and one week later.

In the PZ group, modified Matts' endoscopic scores were significantly improved after treatment compared to baseline in the rectum (p = 0.004), sigmoid colon (p = 0.03) and descending colon (p = 0.04). In the non-PZ group, scores were not significantly improved in the rectum (p = 0.14) and descending colon (p = 0.34), but were improved in the sigmoid colon (p = 0.04). In the PZ group, the Mayo scores at baseline and at Day 8 were 9.1 ± 1.6 and 5.8 ± 2.7 (p = 0.00004), respectively, and in the placebo group, the scores were 8.9 ± 1.7 and 7.4 ± 2.1 (p = 0.009), respectively. Clinical response or remission was significantly better in the PZ group (71%) than in the placebo group (10%).

A zinc-carnosine chelate compound, PZ, enema may become a useful new add-on treatment to accelerate mucosal healing in UC.

Role of lipid peroxidation in the pathogenesis of gastrointestinal diseases has been evaluated by measuring the tissue levels of lipid peroxides as thiobarbituric acid-reactive substances in the animal models as well as human. Recently, N (ε)-(hexanoyl)lysine (HEL) and 4-hydroxy-2-nonenal (HNE) are recognized as reliable and sensitive biomarkers for the early phase and the late phase of lipid peroxidation, respectively. The presence of HNE- and HEL-modified proteins has been demonstrated in in vivo models of several gastrointestinal diseases. In the present review, we introduced HNE-modification of TRPV1 channel in esophageal epithelial cells, HEL-modification of tropomyosin 1 (TMP1) in gastric cancer cells, and HEL-modification of gastrokine 1 in the healing of gastric ulcer.

Protection of the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs including acetylsalicylic acid is a critical issue in the field of gastroenterology. Polaprezinc an anti-ulcer drug, consisting of zinc and L-carnosine, provides gastric mucosal protection against various irritants. In this study, we investigated the protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of the RIE1 rat intestinal epithelial cell line. Confluent rat intestinal epithelial cells were incubated with 70 µM polaprezinc for 24 h, and then stimulated with or without 15 mM acetylsalicylic acid for a further 15 h. Subsequent cellular viability was quantified by fluorometric assay based on cell lysis and staining. Acetylsalicylic acid-induced cell death was also qualified by fluorescent microscopy of Hoechst33342 and propidium iodide. Heat shock proteins 70 protein expression after adding polaprezinc or acetylsalicylic acid was assessed by western blotting. To investigate the role of Heat shock protein 70, Heat shock protein 70-specific small interfering RNA was applied. Cell viability was quantified by fluorometric assay based on cell lysis and staining and apoptosis was analyzed by fluorescence-activated cell sorting. We found that acetylsalicylic acid significantly induced apoptosis of rat intestinal epithelial cells in a dose- and time-dependent manner. Polaprezinc significantly suppressed acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells at its late phase. At the same time, polaprezinc increased Heat shock protein 70 expressions of rat intestinal epithelial cells in a time-dependent manner. However, in Heat shock protein 70-silenced rat intestinal epithelial cells, polaprezinc could not suppress acetylsalicylic acid -induced apoptosis at its late phase. We conclude that polaprezinc-increased Heat shock protein 70 expression might be an important mechanism by which polaprezinc suppresses acetylsalicylic acid-induced small intestinal apoptosis, a hallmark of acetylsalicylic acid-induced enteropathy.

The purpose of the present study was to standardize the experimental rat model of radiation proctitis and to examine the efficacy of polaprezinc on radiation proctitis.

A total of 54 female Wistar rats (5 weeks old) were used. The rats were divided into three groups: those treated with polaprezinc (PZ+), those treated with base alone, exclusive of polaprezinc (PZ-), and those treated without any medication (control). All the rats were irradiated to the rectum. Polaprezinc was prepared as an ointment. The ointment was administered rectally each day after irradiation. All rats were killed on the 10th day after irradiation. The mucosal changes were evaluated endoscopically and pathologically. The results were graded from 0 to 4 and compared according to milder or more severe status, as applicable.

According to the endoscopic findings, the proportion of mild changes in the PZ+, PZ-, and control group was 71.4%, 25.0%, and 14.3% respectively. On pathologic examination, the proportion of low-grade findings in the PZ+, PZ-, and control group was 80.0%, 58.3%, and 42.9% for mucosal damage, 85.0%, 41.7%, and 42.9% for a mild degree of inflammation, and 50.0%, 33.3%, and 4.8% for a shallow depth of inflammation, respectively. The PZ+ group tended to have milder mucosal damage than the other groups, according to all criteria used. In addition, significant differences were observed between the PZ+ and control groups regarding the endoscopic findings, degree of inflammation, and depth of inflammation.

This model was confirmed to be a useful experimental rat model for radiation proctitis. The results of the present study have demonstrated the efficacy of polaprezinc against acute radiation-induced rectal disorders using the rat model.

We investigated the therapeutic effect of polaprezinc (PZ), N-(3-aminopropionyl)-L-histidinato zinc, in rats with experimentally-induced colitis by focusing on calcineurin (CN) inhibition. CN plays a crucial role in T-cell activation and cytokine gene expression and is targeted by immunosuppressants such as cyclosporine and FK506.

Colitis was induced into male Wistar rats by trinitrobenzene sulfonic acid and was treated with intrarectally administered PZ. The inflammation was assessed by the macroscopic damage score, colon wet weight, and proinflammatory mediator expression by RT-PCR analysis. Protein expression of calcineurin and the activation of its substrate, the nuclear factor of activated T cells (NFAT) transcription factor, were also studied. Calcineurin inhibition by PZ was investigated in in vitro experiments using colonic mucosa, purified calcineurin enzyme, and Jurkat T cells.

CN was activated in the colitic mucosa; PZ treatment inhibited CN activation, the expression of proinflammatory cytokines in the mucosa, and thereby ameliorated the experimental colitis in rats. In in vitro experiments, PZ inhibited CN activity, NFAT activation, interleukin-2 expression, and the growth of Jurkat T cells. In the effective concentrations, PZ did not affect cell viability.

Our results suggest that PZ can be used as an immunosuppressive agent for the treatment of colitis through its inhibitory effect on CN activity.

To protect the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs is one of the critical issues in the field of gastroenterology. Polaprezinc (PZ), a gastric muco-protecting agent, has been widely used for the treatment of gastric ulcer and gastritis for its unique effects, such as its strong reactive oxygen species (ROS)-quenching effect. The aim of this study was to clarify the mechanism by which indomethacin-induced small intestinal mucosal injury occurs, by using a rat intestinal epithelial cell line (RIE-1). In addition, the protective role of PZ and the possible mechanism of its effect on indomethacin-induced small intestinal injury were investigated.

Cell death was evaluated by methyl thiazolyl tetrazolium (MTT) assay and a double-staining method with Hoechst33342 dye and propidium iodide. Indomethacin-induced ROS production was evaluated by detecting the oxidation of a redox-sensitive fluorogenic probe, RedoxSensor, and the oxidation of cysteine residues of proteins (protein S oxidation). The activation of cytochrome c, smac/DIABLO, and caspase-3 was assessed by western blotting. In some experiments, PZ or its components, L: -carnosine and zinc, were used.

We found that indomethacin caused apoptosis in RIE-1 cells in a dose- and time-dependent manner. Indomethacin also induced ROS production and an increase in the protein S oxidation of RIE-1. Pretreatment of RIE-1 with PZ or zinc sulfate, but not L: -carnosine, significantly reduced the indomethacin-induced apoptosis. PZ prevented ROS production and the increase in protein S-oxidation. PZ inhibited indomethacin-induced cytochrome c and smac/DIABLO release and subsequent caspase-3 activation.

The protective effect of PZ on indomethacin-induced small intestinal injury may be dependent on its ROS-quenching effect.

The enteric microbiota is a pivotal factor in the development of intestinal inflammation in humans but probiotics, dietary fibres and phytochemicals can have anti-inflammatory effects. The aim of this study was to evaluate the therapeutic effect of multi-strain probiotics and two conceivable prebiotics in an experimental colitis model.

Sprague-Dawley rats were fed a fibre-free diet alone or in combination with Lactobacillus crispatus DSM 16743, L. gasseri DSM 16737 and Bifidobacterium infantis DSM 15158 and/or rye bran and blueberry husks. Colitis was induced by 5% dextran sulphate sodium (DSS) given by oro-gastric tube. Colitis severity, inflammatory markers, gut-load of lactobacilli and Enterobacteriaceae, bacterial translocation and formation of carboxylic acids (CAs) were analysed.

The disease activity index (DAI) was lower in all treatment groups. Viable counts of Enterobacteriaceae were reduced and correlated positively with colitis severity, while DAI was negatively correlated with several CAs, e.g. butyric acid. The addition of probiotics to blueberry husks lowered the level of caecal acetic acid and increased that of propionic acid, while rye bran in combination with probiotics increased caecal CA levels and decreased distal colonic levels. Blueberry husks with probiotics reduced the incidence of bacterial translocation to the liver, colonic levels of myeloperoxidase, malondialdehyde and serum interleukin-12. Acetic and butyric acids in colonic content correlated negatively to malondialdehyde.

A combination of probiotics and blueberry husks or rye bran enhanced the anti-inflammatory effects compared with probiotics or dietary fibres alone. These combinations can be used as a preventive or therapeutic approach to dietary amelioration of intestinal inflammation.

Heme oxygenase (HO)-1 is implicated in cytoprotection in various organs. We tested a possibility that polaprezinc (PZ), an anti-ulcer drug, could induce HO-1 in the gastric mucosa. Male 6-week-old Wistar rats were intragastrically administered PZ. Gastric expression of HO-1 was assessed by real time RT-PCR and western blotting, and localization of HO-1 was observed by in situ hybridization and immunohistochemistry. The levels of HO-1 mRNA were increased in a dose-dependent manner. The levels of HO-1 mRNA were increased 4-fold by PZ at the dose of 200 mg/kg at 3 h as compared with control levels. The levels of immunoreactive HO-1 were increased 3-fold at 6 h. Signals for HO-1 mRNA and immunoreactivity were detected strongly in the surface gastric mucosal cells and moderately in the gastric macrophages. Treatment with an HO-1 inhibitor, stannous mesoporphyrin (SnMP) significantly worsened the HCl-induced acute gastric mucosal lesions and increased the apoptosis of mucosal cells. Mucosal lesions were decreased by pretreatment with PZ, while they were increased by co-administration with SnMP. These data indicate for the first time that PZ is an effective inducer of HO-1 in the stomach. PZ-induced HO-1 functions as a part of the mucosal protective effects of PZ.

Polaprezinc, an anti-ulcer drug, is a chelate compound consisting of zinc and L-carnosine. Polaprezinc has been shown to prevent gastric mucosal injury. The anti ulcer effects of polaprezinc have been ascribed to its antioxidative property. The effect of polaprezinc on ionizing radiation-induced apoptosis was studied in the jejunal epithelial crypt cells of rats. Seven-to eight week-old Wistar rats, which were treated with 100 mg/kg of polaprezinc orally 1h before irradiation or 2% carboxymethyl cellulose sodium in controls, were exposed to whole body X-ray irradiation at 2 Gy. The number of apoptotic cells per jejunum crypt was counted in haematoxylin and eosin stained sections at 0-6 h after irradiation. TUNEL positive cells and immunopositive cells for active caspase-3 per crypt were also counted. Accumulation of p53, p21(WAF1/CIP1) and Bax expression in the jejunum after irradiation were examined by Western blot analyses. Polaprezinc treatment given prior to radiation resulted in a significant reduction in numbers of apoptotic cells, TUNEL positive cells and active caspase-3 immunopositive cells in jejunal crypt cells. Polaprezinc treatment resulted in decreases of p53 accumulation, p21(WAF1/CIP1) and Bax expression after irradiation. Polaprezinc has a protective effect against ionizing radiation induced apoptosis in rat jejunal crypt cells.

Neutrophil accumulation within epithelial crypts and in the intestinal mucosa directly correlates with clinical disease activity and epithelial injury in inflammatory bowel disease (IBD). Current advances have defined the mechanisms by which neutrophils are activated or migrate across endothelial and mucosal epithelial cells. A better understanding of this process will likely provide new insights into novel treatment strategies for IBD. Especially, activated neutrophils produce reactive oxygen and nitrogen species and myeloperoxidase within intestinal mucosa, which induce oxidative stress. Posttranslational modification of proteins generated by these reactive species serves as a "molecular fingerprint" of protein modification by lipid peroxidation-, nitric oxide-, and myeloperoxidase-derived oxidants. Measurement of these modified proteins may serve both as a quantitative index of oxidative stress and an important new biological marker of clinical relevance to IBD. We have succeeded in the clinical development of a novel granulocyte adsorptive apheresis therapy for IBD. In this review, we discuss current advances in defining the role of neutrophil-dependent oxidative stress in IBD.

After intracolonic administration of trinitrobenzene sulphonic acid (TNBS), Sprague-Dawley rats were treated orally either with saline or erdosteine (100 mg/kg per day), a sulfhydryl-containing antioxidant, for 3 days. On the 4th day, rats were decapitated and distal colon was removed for the macroscopic and microscopic damage scoring, for the measurement of malondialdehyde (MDA), glutathione (GSH) and collagen levels, myeloperoxidase (MPO) activity, luminol and lucigenin chemiluminescence (CL) and DNA fragmentation. Lactate dehydrogenase (LDH) activity, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and antioxidant capacity were assayed in blood samples. Colitis caused significant increases in the colonic CL values, macroscopic and microscopic damage scores, MDA and collagen levels, MPO activity and DNA fragmentation, along with a significant decrease in tissue GSH level. Similarly, serum cytokines and LDH were elevated in the saline-treated colitis group as compared with the control group. On the other hand, erdosteine treatment reversed all these biochemical indices, and histopathologic alterations induced by TNBS, suggesting that erdosteine protects the colonic tissue via its radical scavenging and antioxidant activities.

Zinc (Zn) and its binding protein metallothionein (MT) have been proposed to suppress the disease activity in ulcerative colitis. To determine the role of Zn and MT in the dextran sulfate sodium (DSS)-induced model of colitis in mice, a DSS dose-response study was conducted in male C57BL/6 wild-type (MT+/+) and MT-null (MT-/-) mice by supplementing 2%, 3%, and 4% DSS in the drinking water for 6 days. In the intervention study, colitis was induced with 2% DSS, Zn (24 mg/ml as ZnO) was gavaged (0.1 ml) daily, concurrent with DSS administration, and the disease activity index (DAI) was scored daily. Histology, MT levels, and myeloperoxidase (MPO) activity were determined. DAI was increased (P<0.05) by 16% and 21% with 3% and 4% concentrations of DSS, respectively, compared to 2%, evident after 5 days of DSS administration. MPO activity was increased in MT+/+ compared to MT-/- mice and those receiving DSS. Zn administration had a 50% (P<0.05) lower DAI compared to DSS alone. Zn partially prevented the distal colon of MT+/+ by 47% from DSS-induced damage compared to MT-/- mice. MT did not prevent DSS-induced colitis and Zn was partially effective in amelioration of DSS-induced colitis.

We evaluated zinc concentrations in patients with hepatitis C virus (HCV)-positive chronic liver disease and correlated them with the clinical profiles of the patients. A total of 100 patients with chronic hepatitis (CH), 29 with liver cirrhosis (LC), and 6 who were asymptomatic HCV carriers (ASC) were examined. All of the patients were positive for serum HCV RNA. One hundred eighteen HCV antibody-positive hepatocellear carcinoma (HCC) patients and 11 healthy subjects also were included in this study. Serum zinc concentrations were evaluated using conventional atomic absorption spectrometry. The median concentration of zinc in patients with CH was statistically lower than that in healthy control subjects. The median zinc concentrations of the LC and HCC groups were significantly lower than that of the CH group. A significant correlation was observed between the zinc concentrations and the platelet counts and albumin concentrations. The zinc concentrations did not correlate with tumor size and number and decreased with the development of Child-Pugh stage. The cumulative survival rate after therapy for HCC nodules in the low zinc concentration group was significantly lower than in the high group. We conclude that the serum concentration of zinc influences the clinical profiles in patients with C-viral chronic liver disease.

In this study, we investigated the effects of zinc L-carnosine, an anti-ulcer drug, on acetic acid-induced colonic mucosal injury and the correlation of these effects with expression of 72-kDa heat shock proteins (HSP72) and nuclear factor kappa B (NF-kappaB) activation in rat colonic mucosa in vivo. After intrarectal administration of zinc L-carnosine, the rats received intrarectal infusion of 5% acetic acid (1 ml). The colonic mucosal damage was evaluated by macroscopic assessments 24 h after the intrarectal infusion of acetic acid. Expression of HSP72 in rat colonic mucosa was evaluated by Western blot analysis before and after zinc L-carnosine administration. NF-kappaB activation was evaluated by electrophoretic mobility shift assays (EMSA). Zinc L-carnosine inhibited visible damage in rat colonic mucosa by acetic acid. Expression of HSP72 was significantly increased at 6 h after zinc L-carnosine administration. Furthermore, NF-kappaB activation in colonic mucosa was suppressed 6 h after zinc L-carnosine treatment. These results suggested that zinc L-carnosine protects the colonic mucosa against acetic acid by induction of HSP72 and suppression of NF-kappaB activation and zinc L-carnosine may be a novel therapeutic agent for the therapy of inflammatory bowel disease.

The present study was aimed to investigate the effect of ACE inhibition on trinitrobenzene sulphonic acid (TNBS)-induced colonic inflammation in rats by using captopril and lisinopril. In treatment groups, the rats were treated with ACE inhibitors, captopril or lisinopril (0.1 and 1 mg/kg/day; intraperitoneally). The drugs were given 5 min after induction of colitis and the treatment was continued for 3 days. Three days after the induction of colitis, all rats were decapitated. The distal colon was weighed and the mucosal lesions were scored at both macroscopical at microscopic levels. Malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content were assessed in tissue samples. Formation of reactive oxygen species in colonic samples was monitored by using chemiluminescence technique. Serum TNF-alphalevel was assessed in trunk blood. Captopril treatment was found to be beneficial in all parameters, except colonic glutathione content. On the other hand, although stimulation of lipid peroxidation and increase in serum TNF-alpha level were successfully prevented by lisinopril, the morphology of the lesions remained unchanged. In conclusion, sulphydryl and non-sulphydryl ACE inhibitors, captopril and lisinopril do not seem to be similarly effective in TNBS-induced colitis model at least at the doses tested in our study.

Polaprezinc (N-(3-Aminopropionyl)-L-histidinato zinc), an anti-ulcer drug, has been reported to have an anti-inflammatory action in several inflammatory diseases. The aim of this study was to investigate the effect of polaprezinc on dextran sulfate (DSS)-induced colitis in mice.

Mice with colitis induced by DSS were intrarectally treated with polaprezinc (15 mg/kg) or zinc sulfate (7.5 mg/kg) every day after the administration of DSS for 7 days. Disease activity index (DAI) and histological tissue damage were assessed. Levels of myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in the colon were measured. Expression of heat shock protein (HSP) 25 and HSP70 in the colon was analyzed by Western blot analysis.

DAI and histological scores were remarkably reduced in polaprezinc-treated mice with DSS-induced colitis. Polaprezinc suppressed the increase of MPO activity and the production of TNF-alpha and IFN-gamma in the colon tissues of mice with DSS-induced colitis. Expression of HSP25 and HSP70 was remarkably up-regulated in the colon tissues of polaprezinc-treated mice during DSS treatment.

Polaprezinc suppresses DSS-induced colitis in mice, partly through inhibition of production of pro-inflammatory cytokine, suppression of neutrophils accumulation and cytoprotection by overexpression of HSPs. Polaprezinc could be useful in the treatment of inflammatory bowel diseases.

Partially hydrolyzed guar gum (PHGG), a water-soluble dietary fiber produced by a controlled partial enzymatic hydrolysis of guar gum beans, has various physiological actions. The aim of the present study was to elucidate the beneficial effects of PHGG on colonic mucosal damage and on the inflammatory response in a dextran sulfate sodium (DSS) colitis model. After 2 weeks of prefeeding of PHGG, acute colitis was induced with 8% DSS in female BALB/c mice. Colonic mucosal inflammation was evaluated clinically, biochemically and histologically. Mucosal protein contents and mRNA levels of tumor necrosis factor-alpha (TNF-alpha) were determined by immunoassay and reverse transcription polymerase chain reaction. Disease activity scores determined by weight loss, stool consistency and blood in stool in DSS-treated mice were significantly lower in the PHGG-treated mice compared with the control mice. Shortening of the colon was significantly reversed by PHGG. Histological study also showed a reduced infiltration of inflammatory cells, especially neutrophils, and mucosal cell disruption in PHGG-treated mice compared with the control mice. The increases in tissue-associated myeloperoxidase activity and thiobarbituric acid-reactive substances after DSS administration were both significantly inhibited by pretreatment with PHGG. Partially hydrolyzed guar gum also inhibited increases in intestinal TNF-alpha protein and mRNA expression after DSS administration, respectively. These results suggest that chronic ingestion of PHGG prevents the development of DSS-induced colitis in mice via the inhibition of mucosal inflammatory response.

Secretory phospholipase A(2) (sPLA(2)) enzymes have been implicated in the pathogenesis of human inflammatory bowel disease (IBD). In this study we compared the efficacy of a potent, new and highly selective inhibitor of group IIa human sPLA(2) enzyme (5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino)-pentanoic acid; sPLA(2)I), with that of sulfasalazine, in a rat model of trinitrobenzene sulfonic acid (TNBS)-induced colitis. Following a single oral dose of sPLA(2)I (5 mg/kg), pharmacoactive levels of drug were detected in the serum within 15 min and for up to 24 h by liquid chromatography mass spectrometry analysis. Rats treated with sPLA(2)I (5 mg/kg/day) prior to induction of colitis were significantly healthier than TNBS-alone rats, as shown by reduced mortality, improved food intake and increased body weight, and significantly reduced colon myeloperoxidase levels, edema, tumour necrosis factor-alpha levels, and colon macroscopic pathology scores after 8 days. Rats pretreated with sulfasalazine (100 mg/kg/day) also had reduced disease expression markers similar to the sPLA(2)I, but exhibited no improvement in colon edema. This study supports a role for the group IIa sPLA(2) enzyme in pathology associated with the TNBS rat model of IBD, and suggests a possible therapeutic application for selective inhibitors of group IIa sPLA(2) inhibitors in the treatment of IBD.

Oxytocin (OT), a nonapeptide produced in the paraventricular and the supraoptical nuclei in the hypothalamus has a wide range of effects in the body. However, the role of OT on the gastrointestinal (GI) tract has to be settled. OT may participate in the regulation of motility, secretion, blood flow, cell turnover and release of neurotransmitters and/or peptides in the GI tract, possesses antisecretory and antiulcer effects, facilitates wound healing and is involved in the modulation of immune and inflammatory processes. The present work was conducted to assess the possible therapeutic effects of OT against the acetic acid-induced colonic injury in the rat.

Colitis was induced by intracolonic administration of acetic acid (5%) in Sprague-Dawley rats (200-250 g). Either saline or OT (0.5 mg/kg) was injected subcutaneously, immediately after the induction of colitis and repeated two times a day for 4 days. On the 4th day, rats were decapitated and distal 8 cm of the colon were removed for the macroscopic and microscopic damage scoring, determination of tissue wet weight index (WI), malondialdehyde (MDA) levels, an end product of lipid peroxidation; glutathione (GSH) levels, a key antioxidant; and myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. Colonic collagen content, as a fibrosis marker was also determined. Lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-alpha) levels were assayed in serum samples. In the acetic acid-induced colitis, macroscopic and microscopic damage scores, WI, MDA and MPO levels were significantly increased, while GSH levels were decreased when compared to control group (p <0.05-<0.001). Treatment with OT abolished the colitis-induced elevations in damage scores, WI, MDA and MPO levels and restored the GSH levels (p <0.05-0.001). Similarly, acetic acid increased the collagen content of colonic tissues and OT-treatment reduced this value to the level of the control group. Serum LDH and TNF-alpha levels were also elevated in the acetic acid-induced colitis group as compared to control group, while this increase was significantly decreased by OT treatment. The results suggest that OT, which improves the antioxidative state of the colonic tissue and ameliorates oxidative colonic injury via a neutrophil-dependent mechanism, requires further investigation as a potential therapeutic agent in colonic inflammation.

Nuclear factor-kappaB-dependent up-regulation of inflammatory cytokines occurs in inflammatory bowel disease. We investigated the effect of pioglitazone, a peroxisome proliferator-activated receptor-gamma ligand, on dextran sulfate sodium-induced colonic mucosal injury and inflammation in mice. Acute colitis was induced in female mice receiving 0, 1, 3, and 10 mg/kg i.p. of pioglitazone daily. Colonic mucosal inflammation was evaluated chemically and histologically. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in intestinal mucosa as indices of lipid peroxidation and neutrophil infiltration, respectively. Colonic mRNA expression of pro-inflammatory cytokines and inducible nitric oxide synthase was measured by reverse transcription-PCR and nuclear factor-kappaB activation was evaluated by electrophoretic mobility shift assay. Dextran sulfate sodium administration resulted in decreases in body weight and colon length and increases in lipid peroxide and neutrophil accumulation of the intestine. In contrast, co-administration with pioglitazone prevented these changes. Transcripts coding for pro-inflammatory cytokines and inducible nitric oxide were expressed in high levels after the development of colitis, and pioglitazone markedly reduced mRNA expression of these genes. DNA binding activity of nuclear factor-kappaB was markedly increased, whereas in pioglitazone co-treated intestines the effect was significantly reduced. These data suggest that peroxisome proliferator-activated receptor-gamma may be a novel therapeutic target for the therapy of inflammatory bowel disease.

Ellagic acid (EA), a naturally occurring plant phenol, has the antioxidant and anti-inflammatory activities. In the present study, we examined the effect of EA contained in microspheres on the ulcerative colitis induced experimentally in rats by dextran sulfate sodium (DSS). Experimental colitis was induced in male Fisher 344 rats by daily treatment with 3% DSS solution in drinking water for 7 days. EA of microspheres (mcEA: 1 approximately 10 mg/kg as EA contents) was administered p.o. twice daily for 6 days. In a preliminary study, we found that these microsphere capsules, when administered p.o., are effectively dissolved in the proximal to the ileo-cecal junction and distributed to the terminal ileum and the colon. The ulceration area, colon length, and mucosal myeloperoxidase (MPO) activity as well as thiobarbituric acid-reactive substances (TBARS) were measured on 7th day after the onset of DSS treatment. The DSS treatment for 7 days caused severe mucosal lesions in the colon, accompanied with the increases of MPO activity and TBARS as well as the decreases of body weight gain and colon length. Administration of mcEA reduced the severity of DSS-induced colitis in a dose-dependent manner, and a significant effect was observed at 10 mg/kg, the ED50 being 2.3 mg/kg. This mcEA treatment also significantly mitigated changes in various biochemical parameters in the colonic mucosa induced by DSS. Although plain EA (without using microspheres) was also effective in reducing the severity of DSS-induced colitis, this effect was much less potent as compared with that of mcEA; the ED50 was about 15 times higher than that of mcEA. In addition, a significant effect on DSS-induced colitis was also obtained by intra-rectal administration of superoxide dismutase, an anti-oxidative agent. These results suggest that EA prevents the ulcerative colitis induced by DSS, probably by radical scavenging and/or anti-oxidative actions. The microspheres used in this study may be useful for delivering an orally administered drug specifically to the colon.

The protective action of zinc compounds in Crohn's disease-like inflammatory bowel disease in animals has been shown. A similar action of zinc sulfate on ulcerative colitis has not been defined. The present study aimed to delineate the protective action of zinc sulfate and the pathogenic mechanisms of 2,4-dinitrobenzene sulfonic acid (DNBS)-induced ulcerative colitis in rats. Zinc sulfate at different concentrations was given either orally (p.o.) or rectally (p.r.) to rats at 42, 48, 66 and 72 h following the induction of colonic inflammation by DNBS. Rats were killed 96 h after instillation of DNBS rectally to assess the severity of colonic damage, myeloperoxidase and xanthine oxidase activities. The involvement of mast cell degranulation and histamine release in the pathogenesis of DNBS-induced colitis was determined by using a mast cell stabilizer (ketotifen) and histamine receptor blockers (terfenadine and ranitidine). DNBS given rectally produced inflammation and ulceration in rats with a pathology resembling ulcerative colitis. Myeloperoxidase activity but not xanthine oxidase activity was sharply increased by this agent. Intrarectal administration of zinc solution and parenteral injection of histamine blockers significantly reduced tissue damage and myeloperoxidase but not xanthine oxidase activity. Ketotifen, a mast cell stabilizer, also significantly decreased mucosal injury and myeloperoxidase activity in the colon. In conclusion, mast cell degranulation followed by histamine release plays an important role in the pathogenesis of DNBS-induced ulcerative colitis. Zinc given rectally has a therapeutic effect against this colitis model, perhaps through the reduction of inflammation and inhibition of the above pathogenic mechanisms.

H. pylori infection potentiates aspirin-induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.

To determine the role of elastase and active oxygen species (AOS) produced by activated neutrophils in the gastric mucosal injury induced by administration of acidified aspirin to H. pylori-infected Mongolian gerbils.

H. pylori ATCC43504 culture broth was administered by oral gavage to male Mongolian gerbils at 7 weeks of age. After 4 weeks, acidified aspirin (400 mg/kg) was administered orally, and 3 h later, the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemo-attractive cytokine in rodents) were measured in gastric mucosa. To determine the role of elastase or AOS derived from neutrophils in these circumstances, ONO-5046 (an elastase inhibitor), a combination of superoxide dismutase (SOD) and catalase (scavengers of AOS), and polaprezinc (an anti-ulcer agent with anti-inflammatory effects) were administered before aspirin.

ONO-5046 inhibited the increase in gastric erosions and mucosal TBARS induced by administration of aspirin to H. pylori-infected gerbils, but not the increases in MPO activity or KC/GRO contents. A combination of SOD and catalase or polaprezinc significantly reduced gastric erosions, TBARS concentrations, MPO activity and KC/GRO concentration.

These results suggest that neutrophil-derived-elastase and -oxidants play an important role in the gastric mucosal injury induced by administration of aspirin to H. pylori-infected gerbils.

This study was designed to investigate the effects of water-soluble vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), on experimental colitis in rats. Colitis was induced in male Wistar rats weighing 200 grams using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol; 1 ml of TMG dissolved in physiological saline (0.2 mg/ml, 2 mg/ml, 20 mg/ml) was injected intraperitoneally every day for 1 week after the enema. The damage score, wet weight of the colon, and increase in body weight were estimated 1 week after the enema of TNBS. Thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, and the level of alpha-tocopherol or TMG in the colonic mucosa were measured 1 week after the induction of colitis. As a result, increase in body weight was inhibited by the induction of colitis, although the inhibition was reduced in the group treated with TMG. The damage score, wet weight and TBA-RS were increased significantly in the colitis group; however, they were inhibited by the administration of TMG. The alpha-tocopherol level in the colonic mucosa was reduced by the induction of colitis, wheres TMG could not be detected in the colonic mucosa of rats treated with TMG. These results suggest that TMG is effective for the treatment of colitis in rats induced by TNBS.

Oxidative damage is involved in the pathogenic process of idiopathic chronic inflammatory bowel disease. Although specific intervention in the oxidative cascade showed promising results in animal models and preliminary patient trials, the clinical efficacy of antioxidants still has to be established. Mucosa protection, for example by dietary fatty acids, seems to attenuate the intestinal inflammatory process as well but awaits definite clinical proof for the treatment of inflammatory bowel disease.